Draft strips have already become known, which comprise:
a channel-like section to be fixed in a seat at the base of the leaf of a door; PA1 a movable part that is mounted in the fixed channel-like section, which can be moved in height, towards and away from the floor under the door; PA1 at least one weather strip supported by the movable part and intended to rest on the ground when the part is lowered; PA1 a pushing element at at least one end of the movable part intended to be engaged with a corresponding doorjamb to bring about the lowering of the movable part and the resting on the ground of the weather strip when the door is closed; and PA1 at least one means to adjust the position and the action of the movable part.
Also in such embodiments, the movable part is supported by an intermediate section, which is articulated by means of parallelogram-shaped levers and/or by return springs, and the intermediate part can be inserted longitudinally in the fixed channel-like section to simplify its mounting, and it can be extracted for maintenance, replacement, etc.
The draft strips are functional, but also are not free of drawbacks. In fact, the movable part with the seal tends, in general, to compress the seal mainly in its part that is adjacent to the pushing element than in its opposite end part, with the resulting impossibility in any case of completely closing the crack under the door since the seal may remain partially raised in the part that is less compressed. This happens because the movable part is connected to the support section or to the intermediate section by levers and/or by articulation springs, of which only the one closest to the pushing element is moved directly by this element, while that/those which is/are furthest away is/are moved only indirectly by means of the rigidity of the movable part itself. Moreover, in such embodiments, the pushing element is connected to one end of the movable part with the seal with resulting transmission of the forces directly onto the coupling point.
In order to eliminate these drawbacks, two opposite pushing elements have been used, at the ends of the movable part, which interact with opposite jambs of the door. However, the design of the device is complicated, and its function requires specific measures and a very careful working application.
The adjusting means that is provided makes it possible to vary the horizontal position of the movable part to correct the resting on the ground of the, seal according to the inclination of the floor. However, when adjusted, the movable part maintains the new horizontal position even if it is raised from the ground when the door is open, with the result that it remains inclined under the base of the door, without being able to completely return into the resting position in the support section. This may then result in, during the opening or closing of the door, a rubbing of the seal on the floor if the surface of same is irregular or inclined, with a reduction in the crack under the door starting from the jamb against which the door is closed.